Comprehensive DescriptionRead full entry
Desmognathus imitator is a medium-sized desmognathine salamander, with total length reaching up to 70 mm for adult males and up to 100 mm for adult females (Dodd 2004). The tail is cylindrical (Dunn 1927) and lacks a keel (Petranka 1998). This species has 14 costal grooves (Dunn 1927). Like other desmognathines, it has a light line running from the eye to the posterior angle of the jaw (Dodd 2004). The dorsum is brown to nearly black, generally with an indistinct dorsal band composed of a wavy dark brown stripe (Dodd 2004). The belly is gray-black (Dunn 1927; Petranka 1998). Red cheek patches are often present (Dunn 1927; Petranka 1998). Toe tips are not cornified (Petranka 1998).
Variation: Cheek spots may be reddish, orangish, or yellowish (Petranka 1998). Melanistic forms are also seen, with the dorsal surfaces mostly grayish black (Petranka 1998). Individuals of D. imitator lacking cheek spots are morphologically indistinguishable from D. ocoee and can be distinguished only by courtship behavior and molecular evidence (Petranka 1998). Another form was found at Waterrock Knob, N.C. in 1981; individuals from this locality have paired red dorsal spots and a mottled greenish background coloration that matches their wet, vertical rock habitat (Tilley 2000).
Larvae are dark-colored, with distinct lighter dorsal spots ranging from orange to chestnut in color. They may have clearly visible cheek patches (Dodd 2004).
Similar species: In some localities, D. imitator cannot be easily distinguished from the sympatric species D. ocoee; in other localities, these two species have differing color patterns, with D. imitator lacking the distinct light to dark brown dorsal bands that generally characterize D. ocoee, and having red cheeks (lacking in D. ochrophaeus) (Tilley et al. 1978). In the Great Smokies, it can be difficult to distinguish older individuals of D. imitator from older individuals of D. conanti, D. santeetlah, and D. ocoee, as they may all be a uniform darker color (Dodd 2004). For individuals in the Great Smokies that are not uniformly dark, D. imitator can be distinguished from D. ocoee by the lack of a straight edge on the dorsal stripe (vs. presence of a straight edge on the dorsal stripe for D. ocoee); from D. santeetlah by the lack of a light yellow wash on the underside of the limbs and tail (vs. yellow wash present on the underside of limbs and tail for D. santeetlah; and from D. conanti by a black belly and having the tail rounded in cross-section (vs. grayish salt-and-pepper belly and having the tail keeled in cross-section for D. conanti) (Dodd 2004).
Species authority: Dunn (1927).
Etymology: The generic name Desmognathus derives from the Greek word desmos, meaning "ligament," and gnathos, meaning "jaw." It refers to the visibly enlarged bundle of ligaments on the sides of the heads of these salamanders. The specific name imitator refers to the fact that its red cheeks mimic those of the sympatric species Plethodon jordani (Dodd 2004).
Initially this species was described as a subspecies of D. fuscus (Dunn 1927). Subsequently, Tilley et al. (1978) examined genetic variation in populations of D. ochrophaeus in the southern Appalachians, and found that allozyme differences revealed two sympatric forms in the Great Smoky Mountains of Tennessee and North Carolina, with color patterns being identical in some localities. The more widely distributed form was retained as D. ochrophaeus (subsequently referred to as D. ocoee) while the form restricted to the Great Smoky Mountains was recognized as D. imitator (Tilley et al. 1978). The rock-face dwelling form at Waterrock Knob has a different coloration than other populations of D. imitator (Tilley 1985) and is genetically differentiated from streamside and forest populations (Petranka 1998).